This invention relates generally to automotive actuator cables and more particularly to a noise and vibration isolator assembly for a vehicle actuator cable.
Automotive transmission noise and engine vibration are typically transmitted into the passenger compartment by actuator cable assemblies. For example, a vehicle clutch cable assembly having an external sheath surrounding a cable core which extends from a clutch pedal to a clutch actuator fork of a transaxle. Such transaxle noise and vibration, which is especially noticeable during manual transmission shifts, creates an annoyance which is audible and vibrationally felt by the vehicle occupants. Common practice is to use an elastomeric washer in compression to isolate the cable core from the actuator fork, where a hard plastic insert locates the cable sheath in the transaxle bellhousing. Elastomeric washers have performed relatively well in the past when the cable core is unloaded. As soon as the clutch is depressed, however, the cable core side loads the sheath along the length of the core, effectively defeating its isolation and transmitting a higher noise and vibration level. It is clear from the above that an improved isolator design requires isolation of the cable sheath. Known solutions involve expensive designs, such as a cylinder within a rubber cylinder, which places the rubber cylinder solely in either compression or tension.
With reference to prior art FIG. 1, a transaxle, generally indicated by 10', includes a cable actuator assembly 13' having a sheath 14' surrounding a cable core 16' in a spaced manner. The cable core 16' extends from a clutch pedal (not shown) through a series of stepped-end portions of the sheath 14'. The stepped-end portions comprise a series of cylinders 22' and 24' progressively increasing in diameter with the front end cylindrical portion 24' shown in abutment with an annular seating boss 26'. The boss 26' is formed on the aft surface of wall portion 28' of a transaxle bellhousing shown at 30' in FIG. 1. The bellhousing 30' is formed with a longitudinal slot 32' through which the cable core 16' extends. The forward end of the core 16' is secured to an upstanding clutch fork 34' having a wall portion provided with a vertical slit 35' for receiving the cable core 16' therethrough A rubber bushing disc 36', sandwiched between a pair of metal washers 37', has a central bore through which the cable core 16' extends. The cable core 16' terminates in a metal ball-shaped ferrule 38' crimped on its forward end. Prior art FIG. 2 shows an elastomeric washer 40' adapted to be compressed between the boss 26' and forward wall 42' of the cable sheath stepped end 24'.